Biochemical and molecular biomarkers in integument biopsies of free-ranging coastal bottlenose dolphins from southern Brazil.

Adverse effects of exposure to persistent organic pollutants (POPs) threaten the maintenance of odontocete populations. In southern Brazil, coastal bottlenose dolphins from the Laguna Estuarine System (LES) and Patos Lagoon Estuary (PLE) were sampled using remote biopsies during the winter and summer months. Levels of bioaccumulated POPs were measured in the blubber. The activities of glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were also quantified, as were the mRNA transcript levels of aryl hydrocarbon receptor (AhR), AhR nuclear translocator (ARNT), cytochrome P450 1A1-like (CYP1A1), metallothionein 2A (MT2A), GST-π, GPx-4, GR, interleukin 1 alpha (IL-1α), and major histocompatibility complex II (MHCII) in the skin. In general, levels of POPs were similar among sites, sexes, ages and seasons. For most animals, total polychlorinated biphenyl (ΣPCBs) levels were above the threshold level have physiological effects and pose risks to cetaceans. The best-fitting generalized linear models (GLMs) found significant associations between GR, IL-1α and GPx-4 transcript levels, SOD and GST activities, and total polybrominated diphenyl ether (ΣPBDEs) and pesticide levels. GLMs and Kruskal-Wallis analyses also indicated that there were higher transcript levels for most genes and lower GST activity in the winter. These results reinforce the need to consider the influence of environmental traits on biomarker values in wildlife assessments.

Epidemiology of lobomycosis-like disease in bottlenose dolphins Tursiops spp. from South America and southern Africa.

We report on the epidemiology of lobomycosis-like disease (LLD), a cutaneous disorder evoking lobomycosis, in 658 common bottlenose dolphins Tursiops truncatus from South America and 94 Indo-Pacific bottlenose dolphins T. aduncus from southern Africa. Photographs and stranding records of 387 inshore residents, 60 inshore non-residents and 305 specimens of undetermined origin (inshore and offshore) were examined for the presence of LLD lesions from 2004 to 2015. Seventeen residents, 3 non-residents and 1 inshore dolphin of unknown residence status were positive. LLD lesions appeared as single or multiple, light grey to whitish nodules and plaques that may ulcerate and increase in size over time. Among resident dolphins, prevalence varied significantly among 4 communities, being low in Posorja (2.35%, n = 85), Ecuador, and high in Salinas, Ecuador (16.7%, n = 18), and Laguna, Brazil (14.3%, n = 42). LLD prevalence increased in 36 T. truncatus from Laguna from 5.6% in 2007-2009 to 13.9% in 2013-2014, albeit not significantly. The disease has persisted for years in dolphins from Mayotte, Laguna, Salinas, the Sanquianga National Park and Bahía Málaga (Colombia) but vanished from the Tramandaí Estuary and the Mampituba River (Brazil). The geographical range of LLD has expanded in Brazil, South Africa and Ecuador, in areas that have been regularly surveyed for 10 to 35 yr. Two of the 21 LLD-affected dolphins were found dead with extensive lesions in southern Brazil, and 2 others disappeared, and presumably died, in Ecuador. These observations stress the need for targeted epidemiological, histological and molecular studies of LLD in dolphins, especially in the Southern Hemisphere.

Abundance of bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae), inhabiting the Patos Lagoon estuary, southern Brazil: implications for conservation

A new mark-recapture abundance estimate and a photographic census were carried out to investigate the possible decline in the abundance of the bottlenose dolphins, Tursiops truncatus (Montagu, 1821), in the Patos Lagoon estuary due to the high levels of bycatch mortality which occurred between 2002 and 2006 in oceanic coastal areas close to the estuary. Fourteen systematic boat surveys were conducted between August and early December 2005 to photo-identify the bottlenose dolphins. The estimated number of animals, with long-lasting marks, in the population obtained from Chapman's and Mth models were 51 (95% CI = 49-53) and 52 (95% CI = 51-60), respectively. Taking into account the proportion of dolphins with long-lasting marks in the population, the total estimated population size ranged between 84 (95% CI = 76-93) and 86 (95% CI = 78-95) individuals, respectively, which was very similar to the 84 individuals revealed by the population census. Our results did not differ from the abundance estimate carried out in 1998, prior to the high fishing-related mortality event, suggesting that the population is stable. Plausible argument to explain the stability of the population is that some carcasses found on the oceanic coastal beaches near Patos Lagoon estuary come from animals that do not belong to the estuary community. Future studies should investigate fine-scale habitat partition between estuarine and adjacent coastal dolphins. If the existence of different communities living in close proximity (estuarine and coastal areas near to the estuary) is confirmed, a new abundance estimate is needed to access the conservation status of bottlenose dolphins in this region.

Abundance of bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae), inhabiting the Patos Lagoon estuary, southern Brazil: implications for conservation

A new mark-recapture abundance estimate and a photographic census were carried out to investigate the possible decline in the abundance of the bottlenose dolphins, Tursiops truncatus (Montagu, 1821), in the Patos Lagoon estuary due to the high levels of bycatch mortality which occurred between 2002 and 2006 in oceanic coastal areas close to the estuary. Fourteen systematic boat surveys were conducted between August and early December 2005 to photo-identify the bottlenose dolphins. The estimated number of animals, with long-lasting marks, in the population obtained from Chapman's and Mth models were 51 (95% CI = 49-53) and 52 (95% CI = 51-60), respectively. Taking into account the proportion of dolphins with long-lasting marks in the population, the total estimated population size ranged between 84 (95% CI = 76-93) and 86 (95% CI = 78-95) individuals, respectively, which was very similar to the 84 individuals revealed by the population census. Our results did not differ from the abundance estimate carried out in 1998, prior to the high fishing-related mortality event, suggesting that the population is stable. Plausible argument to explain the stability of the population is that some carcasses found on the oceanic coastal beaches near Patos Lagoon estuary come from animals that do not belong to the estuary community. Future studies should investigate fine-scale habitat partition between estuarine and adjacent coastal dolphins. If the existence of different communities living in close proximity (estuarine and coastal areas near to the estuary) is confirmed, a new abundance estimate is needed to access the conservation status of bottlenose dolphins in this region.

Abundance of bottlenose dolphins, Tursiops truncatus (Cetacea: Delphinidae), inhabiting the Patos Lagoon estuary, southern Brazil: implications for conservation

A new mark-recapture abundance estimate and a photographic census were carried out to investigate the possible decline in the abundance of the bottlenose dolphins, Tursiops truncatus (Montagu, 1821), in the Patos Lagoon estuary due to the high levels of bycatch mortality which occurred between 2002 and 2006 in oceanic coastal areas close to the estuary. Fourteen systematic boat surveys were conducted between August and early December 2005 to photo-identify the bottlenose dolphins. The estimated number of animals, with long-lasting marks, in the population obtained from Chapman's and Mth models were 51 (95% CI = 49-53) and 52 (95% CI = 51-60), respectively. Taking into account the proportion of dolphins with long-lasting marks in the population, the total estimated population size ranged between 84 (95% CI = 76-93) and 86 (95% CI = 78-95) individuals, respectively, which was very similar to the 84 individuals revealed by the population census. Our results did not differ from the abundance estimate carried out in 1998, prior to the high fishing-related mortality event, suggesting that the population is stable. Plausible argument to explain the stability of the population is that some carcasses found on the oceanic coastal beaches near Patos Lagoon estuary come from animals that do not belong to the estuary community. Future studies should investigate fine-scale habitat partition between estuarine and adjacent coastal dolphins. If the existence of different communities living in close proximity (estuarine and coastal areas near to the estuary) is confirmed, a new abundance estimate is needed to access the conservation status of bottlenose dolphins in this region.